Abrasive polishing and grinding disk assembly



Och 1953 E. L. RICH ET AL 2,654,193

ABRASIVE POLISHING AND GRINDING DISK ASSEMBLY Filed Nov. 8, 1951 A; M nmm 0 figuen //2 I I. [am

I I a 5 i (S I l 11/ a 411 ATTORNEY The spider 5 is centrally bored and threaded as at 2|, and the threaded section I! of the spindle nut H threadedly engages therewith, with the back face of the spider in abutting relation with the shouldered section 18 of the nut H. An enlarged bore or recess 22 is formed on the front wall of the spider concentric with the reduced section I9 of the nut, the inner peripheral side wall of said recess being slightly undercut'at an oblique angle to receive a cup-shaped metallic hub insert S which forms the center of an abrasive disc D and to which it is clamped.

The insert S is clamped to the peripheral edge 23 of the centrally disposed opening in the abrasive disc and comprises inner and outer preferably stamped sections 24 and 25 respectively, the

peripheral edge 23 of the abrasive material being turned inwardly between the members 24 and 25, which members are formed with grooved peripheral walls 26-26 to snugly nest in the undercut curved side wall of the recess in the spider. Thence, the inner edge sections of the members 24 and 25 are turned inwardly and toothed as at T to fit and slidably engage the splines 28 pro vided on the nut section 19, these toothed edges of the members 24 and 25 being tightly pressed together, while the side wall is firmly clamped to the material 23, and a flange 2! is provided on the upper end of the outer section 25 to reinforce and prevent a sharp bend in the abrasive disc material at this point. It should be stated that the enlarged recess 22 is of suificient diameter to permit the cup-shaped member S to be readily slipped into and removed therefrom.

A plurality of circumferentially spaced, angularly disposed bores 28 are provided in the spider 5, these bores extending obliquely inwardly toward the axis of the hub H, said bores being enlarged and shouldered as at 29, and locking pins 38 are mounted therein, each pin being formed with a ball-shaped end 31 which projects into the recess 22 for clampingly engaging the inner marginal rim 26 of the cup-shaped insert member S to securely lock the same in position.

Enlarged heads 32 are formed on the pins 30 and are accommodated in the bores 29, and coil springs 33 are interposed between the head 32 and the inner end of the enlarged bore to normally urge the pins 30 to their retracted position, and as clearly indicated in Fig. 3 of the drawing.

The inner face of the spider '5 is beveled as at 34, and a dished contact washer 35 is mounted on the spindle nut H and overlies said beveled surface, the enlarged heads 32 of the locking pins being ball-shaped as at 36 for engagement with the contact washer 35, and a manually operable locking collar 31 is threaded on the threaded section [5 of the nut l I, said collar being knurled as at 38 so that it can be readily manipulated, the shoulder 39 engaging the inner edge of the washer 35 for urging the pins to locked position and causing the ball nosed ends 3i to be presented in grippin engagement with the crimped portions of the flexible disc-shaped abrasive disc D. The knurled portion 38 of the collar 37 provides a finger grip surface to enable the actuating locking collar to be manipulated without the use of wrenches, screw drivers or other special tools.

In operation, the device is well suited to easy and rapid changing of the abrasive disc-shaped assembly. To release, it is merely necessary to manually back olf the locking collar S'l' which permits the springs 33 to yieldingly urge the looking pins 30 outwardly, thus releasing pressure on the lockin washer 35, after which the insert and disc assembly is free for removal, and the abrasive disc can be removed and a replacement inserted.

To look the new disc in position, the abrasive disc D m first placed in position with the toothed sections T in engagement with the splines 20 of the spindle nut; the threaded locking collar 31 is then rotated to force the contact washer 35 into engagement with the ball-shaped ends 36 of the locking pins 30 so as to force the same inwardly into their locked position (see Fig. 1 of the drawing), and thereby securely anchor the abrasive disc in position.

The mounting of the abrasive disc and the backing plate I9 is particularly useful at high speeds, serving to absorb much of the shock otherwise incident to the abrasive disc and permitting the use of a less sturdy and more economical disc.

It is obvious that the grinding disc assembly is adapted to be easily and conveniently attached to the spindle of a portable or other grinding machine (not shown).

While the invention illustrated and described is illustrative of the preferred form of the construction of the invention, it is to be understood that the same does not limit the invention to the precise detail of the structure as shown, and that other variations and modifications may come within the scope of the appended claims.

What we claim is:

1. In a polishing and grinding disc assembly, a hub structure having a central opening adapted to be secured to a power spindle and having a central recess in the outer face thereof, a flexible backing disc secured to said hub, a flexible disc-shaped abrasive sheet, a central hub portion for said sheet having an annular peripheral groove and inwardly angled, circumferentially spaced locking pins carried by said hub structure havin their ends presented to said groove to clamp the central hub of the abrasive sheet in said recess.

2. In a polishing and grinding disc assembly, a disc-like housing adapted to be secured to a power spindle, and having a central recess, a flexible disc-shaped abrasive sheet removably mounted on said disc-like housing and formed with a metallic hub having an annular peripheral groove therein, said hub being received in said recess for retaining said abrasive sheet in said recess, and locking pins mounted adjacent the axis of the disc-like housing havin their ends presented to said groove to engage and lock the central hub portion of the abrasive sheet in said recess.

3. In a polishing and grinding disc assembly, a hub structure having a central opening for being received on a power spindle and a concentric central recess in one end wall thereof, a backing disc secured to said hub, a flexible disc-shaped abrasive sheet formed with a metallic central hub non-rotatably received in said recess, said hub having a peripheral groove, and locking pins slidably mounted in the hub and arranged in angular relation to the hub axis with their ends presented in looking engagement to the groove in the central hub portion of the abrasive disc to clamp the same and thereby lock the abrasive sheet in position.

4. In a polishing and grinding disc assembly, a hub structure having a central opening for being received on a power spindle, said hub structure being provided in one wall with a concentricannular recess, a backing disc secured to said hub structure, a flexible disc-shaped abrasive sheet, a hub for said sheet having an annular peripheral groove, removably accommodated in said recess, locking pins slidably mounted in said hub structure and arranged in annular spaced relation at an angle to the axis of said hub with their ends projecting into said recess, said pins being arranged to engage the peripheral groove in the hub and clamp the abrasive sheet in position, an actuator on said hub structure having an inclined wall adapted to engage said pins to urge the ends thereof into the annular groove, and yielding spring means for normally urging said pins to a retracted position.

5. In a polishing and grinding disc assembly, a hub structure having a central opening for being received on a power spindle, said hub structure being provided in an end wall thereof with an annular recess, the inner peripheral wall of which slopes obliquely away from the axis of said hub structure, a disc-shaped abrasive sheet including a hub insert adapted to be received in said recess, said insert being formed with an annular peripheral groove, a series of obliquely disposed locking pins slidably mounted in said hub with their ends projecting into said recess for clamping the hub insert of the disc shaped abrasive sheet in the annular recess and securing the sheet in position, a frusto-conical member mounted on the hub to engage the opposite ends of said pins to urge the same into locking engagement, a screw actuator threaded on said hub for moving said member axially, and springs mounted on said pins to yieldingly normally urge the same out of locking engagement.

6. In a polishing and grinding disc assembly for mounting on a power spindle, a disc-like housing having a central annular recess in the outer face thereof, a flexible disc-shaped abrasive sheet, a centrally disposed hub for said sheet removably and non-rotatably secured in said recess, circumferentially spaced locking pins disposed at an angle with relation to the axis of said housing and sheet carried by said housing and presented to said hub in opposed relation to clamp said hub and thereby secure said sheet in position, means threaded on said housing to engage said pins and actuate them into clamping engagement with said hub.

'7. In a polishing and grinding disc assembly for mounting on a power spindle, a disc-like housing a central annular recess in the outer face thereof, a flexible disc-shaped abrasive sheet for mounting on the face of said housing, a hub for said sheet removably and non-rotatably received in said recess, said hub having an annular groove in the peripheral wall thereof, inwardly angled, diametrically opposed locking pins carried by said disc to clamp against the marginal Wall of said groove and maintain said hub and sheet in locked position, and means for securing said pins in locked position.

8. The combination defined in claim 7 in which a reduced portion of said housing projects centrally into said recess, and splines are provided on the peripheral wall thereof, said hub being formed with a central opening to receive said reduced portion when said hub is mounted on said housing and with spline openings to accommodate said splines and retain said housing and said hub in non-rotatable relation.

EDWARD L. RICH. JOHN K. BAUER. WILLIAM E. DENGEL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 727,557 Robinson May 5, 1903 2,217,791 Burleigh Oct. 15, 1940 2,402,691 Stever June 25, 1946 

